The yup npm package is a JavaScript schema builder for value parsing and validation. It enables developers to construct schemas for objects, arrays, strings, numbers, booleans, and more, to validate the shape and content of data against those schemas. It is often used in the context of form validation on both the client and server sides.
Object Shape Validation
Validates the shape of an object, ensuring that it has specific fields with data types and constraints like strings being required, numbers being positive integers, and strings matching email or URL patterns.
{"const schema = yup.object().shape({ name: yup.string().required(), age: yup.number().required().positive().integer(), email: yup.string().email(), website: yup.string().url() }); schema.isValid({ name: 'John', age: 24, email: 'john@example.com', website: 'http://example.com' }).then(valid => { console.log(valid); // true });"}Array Validation
Validates arrays, ensuring that they contain elements of a specific type and adhere to constraints, such as all elements being positive numbers.
{"const schema = yup.array().of(yup.number().positive()).required(); schema.isValid([1, 2, 3]).then(valid => { console.log(valid); // true });"}String Validation
Validates strings, ensuring they meet criteria such as being required, having a minimum length, and not exceeding a maximum length.
{"const schema = yup.string().required().min(2).max(10); schema.isValid('Hello').then(valid => { console.log(valid); // true });"}Number Validation
Validates numbers, ensuring they are positive, integers, and below a certain value.
{"const schema = yup.number().positive().integer().lessThan(100); schema.isValid(50).then(valid => { console.log(valid); // true });"}Date Validation
Validates dates, ensuring they fall within a specified range.
{"const schema = yup.date().min(new Date(2000, 0, 1)).max(new Date(2020, 12, 31)); schema.isValid(new Date(2010, 6, 15)).then(valid => { console.log(valid); // true });"}Custom Validation
Allows for custom validation functions to be defined, providing flexibility for more complex validation scenarios.
{"const schema = yup.string().test('is-john', 'The name must be John', value => value === 'John'); schema.isValid('John').then(valid => { console.log(valid); // true });"}Joi is a powerful schema description language and data validator for JavaScript. It offers a similar API to yup but with a broader feature set and more detailed error messages. Joi is often considered more heavyweight compared to yup.
Ajv is a JSON schema validator that supports draft-06/07/2019-09 of JSON Schema. It is known for its performance and is typically used for validating JSON data structures. Unlike yup, Ajv is based on pre-defined JSON schemas rather than a programmatic API.
Validator is a library of string validators and sanitizers. It is more focused on string validation and does not provide object schema validation like yup. It's useful for simple validation tasks without the need for defining complex schemas.
Class-validator works with TypeScript and uses decorators to define validation rules within class models. It is tightly integrated with TypeScript and is a good choice for projects that are already using TypeScript and decorators.
Yup is a JavaScript object schema validator and object parser. The API and style is stolen heavily inspired
by Joi, which is an amazing library but is generally too large and difficult
to package for use in a browser. Yup is a leaner in the same spirit without some of the fancy features.
You can use it on the server as well, but in that case you might as well just use Joi.
Yup is also a good bit less opinionated than joi, allowing for custom transformations and async validation.
It also allows "stacking" conditions via when for properties that depend on more than one other sibling or
child property. Yup separates the parsing and validating functions into separate steps so it can be used to parse
json separate from validating it, via the cast method.
Table of Contents generated with DocToc
yup
yup.reach(schema: Schema, path: string, value: ?object, context: ?object): Schemayup.addMethod(schemaType: Schema, name: string, method: ()=> Schema): voidyup.ref(path: string, options: { contextPrefix: string }): Refyup.lazy((value: any) => Schema): LazyValidationError(errors: string | Array<string>, value: any, path: string)mixed.clone(): Schemamixed.label(label: string): Schemamixed.meta(metadata: object): Schemamixed.describe(): SchemaDescriptionmixed.concat(schema: Schema)mixed.validate(value: any, options: ?object, callback: ?function): Promise<any, ValidationError>mixed.isValid(value: any, options: ?object, callback: ?function): Promise<boolean>mixed.cast(value: any): anymixed.isType(value: any): booleanmixed.strict(isStrict: boolean = false): Schemamixed.strip(stripField: boolean = true): Schemamixed.withMutation(builder: (current: Schema) => void): voidmixed.default(value: any): Schemamixed.default(): Anymixed.nullable(isNullable: boolean = false): Schemamixed.required(message: ?string): Schemamixed.typeError(message: string): Schemamixed.oneOf(arrayOfValues: Array<any>, string: ?message): Schema Alias: equalsmixed.notOneOf(arrayOfValues: Array<any>, string: ?message)mixed.when(keys: string | Array<string>, builder: object | (value, schema)=> Schema): Schemamixed.test(name: string, message: string, test: function, callbackStyleAsync: ?boolean): Schemamixed.test(options: object): Schemamixed.transform((currentValue: any, originalValue: any) => any): Schemastring.required(message: ?string): Schemastring.min(limit: number | Ref, message: ?string): Schemastring.max(limit: number | Ref, message: ?string): Schemastring.matches(regex: Regex, message: ?string): Schemastring.email(message: ?string): Schemastring.url(message: ?string): Schemastring.ensure(): Schemastring.trim(message: ?string): Schemastring.lowercase(message: ?string): Schemastring.uppercase(message: ?string): Schemanumber.min(limit: number | Ref, message: ?string): Schemanumber.max(limit: number | Ref, message: ?string): Schemanumber.positive(message: ?string): Schemanumber.negative(message: ?string): Schemanumber.integer(message: ?string): Schemanumber.truncate(): Schemanumber.round(type: 'floor' | 'ceil' | 'trunc' | 'round' = 'round'): SchemaYou define and create schema objects. Schema objects are immutable, so each call of a method returns a new schema object.
try it out using tonicdev! https://tonicdev.com/570c52590a85f71200eb09ba/yup
var yup = require('yup')
var schema = yup.object().shape({
name: yup.string().required(),
age: yup.number().required().positive().integer(),
email: yup.string().email(),
website: yup.string().url(),
createdOn: yup.date().default(function() {
return new Date
})
})
//check validity
schema.isValid({
name: 'jimmy',
age: 24
})
.then(function(valid){
valid // => true
})
//you can try and type cast objects to the defined schema
schema.cast({
name: 'jimmy',
age: '24',
createdOn: '2014-09-23T19:25:25Z'
})
// => { name: 'jimmy', age: 24, createdOn: Date }
yupThe module export.
var yup = require('yup')
yup.mixed
yup.string
yup.number
yup.boolean // also aliased as yup.bool
yup.date
yup.object
yup.array
yup.reach
yup.addMethod
yup.ValidationError
yup.reach(schema: Schema, path: string, value: ?object, context: ?object): SchemaFor nested schema's yup.reach will retrieve a nested schema based on the provided path.
For nested schema that need to resolve dynamically, you can provide a value and optionally
a context object.
var schema = object().shape({
nested: object()
.shape({
arr: array().of(
object().shape({ num: number().max(4) }))
})
})
reach(schema, 'nested.arr.num')
reach(schema, 'nested.arr[].num')
reach(schema, 'nested.arr[1].num')
reach(schema, 'nested["arr"][1].num')
yup.addMethod(schemaType: Schema, name: string, method: ()=> Schema): voidAdds a new method to the core schema types. A friendlier convenience method for schemaType.prototype[name] = method.
yup.addMethod(yup.date, 'format', function(formats, parseStrict) {
return this.transform(function(value, originalValue){
if ( this.isType(value) ) return value
value = Moment(originalValue, formats, parseStrict)
return date.isValid() ? date.toDate() : invalidDate
})
})
yup.ref(path: string, options: { contextPrefix: string }): RefCreates a reference to another sibling or sibling descendant field. Ref's are resolved at validation/cast time and supported where specified. Ref's are evaluated in in the proper order so that the ref value is resolved before the field using the ref (be careful of circular dependencies!).
var schema = object({
baz: ref('foo.bar'),
foo: object({
bar: string()
})
x: ref('$x')
})
inst.cast({ foo: { bar: 'boom' } }, { context: { x: 5 } })
// { baz: 'boom', x: 5, { foo: { bar: 'boom' } }, }
yup.lazy((value: any) => Schema): Lazycreates a schema that is evaluated at validation/cast time. Useful for creating recursive schema like Trees, for polymophic fields and arrays.
CAUTION! When defining parent-child recursive object schema, you want to reset the default()
to undefined on the child otherwise the object will infinitely nest itself when you cast it!.
var node = object({
id: number(),
child: yup.lazy(() =>
node.default(undefined)
)
})
let renderable = yup.lazy(value => {
switch (typeof value) {
case 'number':
return number()
case 'string':
return string()
default:
return mixed()
}
})
let renderables = array().of(renderable)
ValidationError(errors: string | Array<string>, value: any, path: string)Thrown on failed validations, with the following properties
name: "ValidationError"path: a string, indicating where there error was thrown. path is empty at the root level.errors: array of error messagesinner: in the case of aggregate errors, inner is an array of ValidationErrors throw earlier in the
validation chain. When the abortEarly option is false this is where you can inspect each error thrown,
alternatively errors will have all the of the messages from each inner error.Creates a schema that matches all types. All types inherit from this base type
var schema = yup.mixed();
schema.isValid(undefined, function(valid){
valid //=> true
})
mixed.clone(): SchemaCreates a deep copy of the schema. Clone is used internally to return a new schema with every schema state change.
mixed.label(label: string): SchemaOverrides the key name which is used in error messages.
mixed.meta(metadata: object): SchemaAdds to a metadata object, useful for storing data with a schema, that doesn't belong the cast object itself.
mixed.describe(): SchemaDescriptionCollects schema details (like meta, labels, and active tests) into a serializable description object.
SchemaDescription {
type: string,
label: string,
meta: object,
tests: Array<string>
}
mixed.concat(schema: Schema)Creates a new instance of the schema by combining two schemas. Only schemas of the same type can be concatenated.
mixed.validate(value: any, options: ?object, callback: ?function): Promise<any, ValidationError>Returns the value (a cast value if isStrict is false) if the value is valid, and returns the errors otherwise.
This method is asynchronous and returns a Promise object, that is fulfilled with the value, or rejected
with a ValidationError. If you are more comfortable with Node style callbacks, then you can provide one
to be called when the validation is complete (called with the Error as the first argument, and value
as the second).
The options argument is an object hash containing any schema options you may want to override
(or specify for the first time).
Options = {
strict: boolean = false;
abortEarly: boolean = false;
stripUnknown: boolean = false;
recursive: boolean = true;
context: ?object;
}
strict: only validate the input, and skip and coercion or transformationabortEarly: return from validation methods on the first error rather
than after all validations run.stripUnknown: remove unspecified keys from objects.recursive: when false validations will not descend into nested schema
(relevant for objects or arrays).context: any context needed for validating schema conditions (see: when())schema.validate({ name: 'jimmy',age: 24 })
.then(function(value){
value // => { name: 'jimmy',age: 24 }
})
schema.validate({ name: 'jimmy', age: 'hi' })
.catch(function(err){
err.name // 'ValidationError'
err.errors // => ['age must be a number']
})
//or with callbacks
schema.validate({ name: 'jimmy',age: 24 }, function(err, value){
err === null // true
value // => { name: 'jimmy',age: 24 }
})
schema.validate({ name: 'jimmy', age: 'hi' }, function(err, value){
err.name // 'ValidationError'
err.errors // => ['age must be a number']
value === undefined // true
})
mixed.isValid(value: any, options: ?object, callback: ?function): Promise<boolean>Returns true when the passed in value matches the schema. if false then the schema also has a .errors
field which is an array of validation error messages (strings), thrown by the schema. isValid
is asynchronous and returns a Promise object. If you are more comfortable with Node style callbacks,
providing a function as the last argument will opt into that interface.
Takes the same options as validate().
mixed.cast(value: any): anyAttempts to coerce the passed in value to a value that matches the schema. For example: '5' will
cast to 5 when using the number() type. Failed casts generally return null, but may also
return results like NaN and unexpected strings.
mixed.isType(value: any): booleanRuns a type check against the passed in value. It returns true if it matches,
it does not cast the value. When nullable() is set null is considered a valid value of the type.
You should use isType for all Schema type checks.
mixed.strict(isStrict: boolean = false): SchemaSets the strict option to true. Strict schemas skip coercion and transformation attempts,
validating the value "as is".
mixed.strip(stripField: boolean = true): SchemaMarks a schema to be removed from an output object. Only works as a nested schema.
let schema = object({
useThis: number(),
notThis: string().strip()
})
schema.cast({ notThis: 'foo', useThis: 4 }) // { useThis: 4 }
mixed.withMutation(builder: (current: Schema) => void): voidFirst the legally required Rich Hickey quote:
If a tree falls in the woods, does it make a sound?
If a pure function mutates some local data in order to produce an immutable return value, is that ok?
withMutation allows you to mutate the schema in place, instead of the default behavior which clones before each change.
Generally this isn't necessary since the vast majority of schema changes happen during the initial
declaration, and only happen once over the lifetime of the schema, so performance isn't an issue.
However certain mutations do occur at cast/validation time, (such as conditional schema using when()), or
when instantiating a schema object.
object()
.shape({ key: string() })
.withMutation(schema => {
return arrayOfObjectTests.forEach(test => {
schema.test(test)
})
})
mixed.default(value: any): SchemaSets a default value to use when the value is undefined (or null when the schema is not nullable).
Defaults are created after transformations are executed, but before validations, to help ensure that safe
defaults are specified. The default value will be cloned on each use, which can incur performance penalty
for objects and arrays. To avoid this overhead you can also pass a function that returns an new default.
yup.string.default('nothing');
yup.object.default({ number: 5}); // object will be cloned every time a default is needed
yup.object.default(() => ({ number: 5})); // this is cheaper
yup.date.default(() => new Date()); //also helpful for defaults that change over time
mixed.default(): AnyCalling default with no arguments will return the current default value
mixed.nullable(isNullable: boolean = false): SchemaIndicates that null is a valid value for the schema. Without nullable()
null is treated as a different type and will fail isType() checks.
mixed.required(message: ?string): SchemaMark the schema as required. All field values apart from undefined meet this requirement.
mixed.typeError(message: string): SchemaDefine an error message for failed type checks. The ${value} and ${type} interpolation can
be used in the message argument.
mixed.oneOf(arrayOfValues: Array<any>, string: ?message): Schema Alias: equalsWhitelist a set of values. Values added are automatically removed from any blacklist if they are in it.
The ${values} interpolation can be used in the message argument.
var schema = yup.mixed().oneOf(['jimmy', 42]);
schema.isValid(42) //=> true
schema.isValid('jimmy') //=> true
schema.isValid(new Date) //=> false
mixed.notOneOf(arrayOfValues: Array<any>, string: ?message)Blacklist a set of values. Values added are automatically removed from any whitelist if they are in it.
The ${values} interpolation can be used in the message argument.
var schema = yup.mixed().notOneOf(['jimmy', 42]);
schema.isValid(42) //=> false
schema.isValid(new Date) //=> true
mixed.when(keys: string | Array<string>, builder: object | (value, schema)=> Schema): SchemaAdjust the schema based on a sibling or sibling children fields. You can provide an object
literal where the key is is value or a matcher function, then provides the true schema and/or
otherwise for the failure condition.
is conditions are strictly compared (===) if you want to use a different form of equality you
can provide a function like: is: (value) => value == true.
Like joi you can also prefix properties with $ to specify a property that is dependent
on context passed in by validate() or isValid. when conditions are additive.
var inst = yup.object({
isBig: yup.boolean(),
count: yup.number()
.when('isBig', {
is: true, // alternatively: (val) => val == true
then: yup.number().min(5),
otherwise: yup.number().min(0)
})
.when('$other', (other, schema) => other === 4
? schema.max(6)
: schema)
})
inst.validate(value, { context: { other: 4 }})
You can also specify more than one dependent key, in which case each value will be spread as an argument.
var inst = yup.object({
isSpecial: yup.bool()
isBig: yup.bool(),
count: yup.number()
.when(['isBig', 'isSpecial'], {
is: true, // alternatively: (isBig, isSpecial) => isBig && isSpecial
then: yup.number().min(5),
otherwise: yup.number().min(0)
})
})
inst.validate({
isBig: true,
isSpecial: true,
count: 10
})
Alternatively you can provide a function the returns a schema (called with the value of the key and the current schema).
var inst = yup.object({
isBig: yup.boolean(),
count: yup.number()
.when('isBig', (isBig, schema) => {
return isBig ? schema.min(5) : schema.min(0)
})
})
inst.validate({ isBig: false, count: 4 })
mixed.test(name: string, message: string, test: function, callbackStyleAsync: ?boolean): SchemaAdds a test function to the validation chain. Tests are run after any object is cast. Many types have some tests built in, but you can create custom ones easily. In order to allow asynchronous custom validations all tests are run asynchronously. A consequence of this is that test execution order cannot be guaranteed.
All tests must provide a name, an error message and a validation function that must return
true or false or a ValidationError. To make a test async return a promise that resolves true
or false or a ValidationError. If you prefer the Node callback style, you can pass true for callbackStyleAsync
and the validation function will pass in an additional done function as the last parameter to
be called with the validity.
for the message argument you can provide a string which is will interpolate certain values
if specified using the ${param} syntax. By default all test messages are passed a path value
which is valuable in nested schemas.
the test function is called with the current value, along with path and context if they exist.
For more advanced validations you can use the alternate signature to provide more options (see below):
var jimmySchema = yup.string()
.test('is-jimmy', '${path} is not Jimmy', value => value === 'jimmy');
// or make it async by returning a promise
var asyncJimmySchema = yup.string()
.test('is-jimmy', '${path} is not Jimmy', function (value){
return fetch('/is-jimmy/' + value)
.then(response => response.responseText === 'true')
});
// or callback style for asynchrony
var asynCallbackJimmySchema = yup.string()
.test('is-jimmy', '${path} is not Jimmy', test, true);
function test(value, done){
// error argument is for exceptions, not an failed tests
done(null, value === 'jimmy')
}
schema.isValid('jimmy').then(...) //=> true
schema.isValid('john').then(...) //=> false
schema.errors // => [ 'this is not Jimmy!']
test functions are called with a special context, or this value, that exposes some useful metadata and functions.
this.path: the string path of the current validationthis.schema: the resolved schema object that the test is running against.this.options: the options object that validate() or isValid() was called withthis.parent: in the case of nested schema, this is the value of the parent objectthis.createError(Object: { path: String, message: String }): create and return a
validation error. Useful for dynamically setting the path, or more likely, the error message.
If either option is omitted it will use the current path, or default message.mixed.test(options: object): SchemaAlternative test(..) signature. options is an object containing some of the following options:
Options = {
// Unique name identifying the test
name: string;
// test function, determines schema validity
test: (value: any) => boolean;
// The validation error message
message: string;
// values passed to message for interpolation
params: ?object;
// mark the test as exclusive, meaning only one of the same can be active at once
exclusive: boolean = false;
// opt into the node callback style over promises for async validation
useCallback: boolean: false;
}
In the case of mixing exclusive and non-exclusive tests the following logic is used. If a non-exclusive test is added to a schema with an exclusive test of the same name the exclusive test is removed and further tests of the same name will be stacked.
If an exclusive test is added to a schema with non-exclusive tests of the same name the previous tests are removed and further tests of the same name will replace each other.
var schema = yup.mixed().test({
name: 'max',
exclusive: true,
params: { max },
message: '${path} must be less than ${max} characters',
test: value => value == null || value.length <= max
});
mixed.transform((currentValue: any, originalValue: any) => any): SchemaAdds a transformation to the transform chain. Transformations are central to the casting process,
default transforms for each type coerce values to the specific type (as verified by isType()).
transforms are run before validations and only applied when strict is true. Some types have built in transformations.
Transformations are useful for arbitrarily altering how the object is cast, however, you should take care
not to mutate the passed in value. Transforms are run sequentially so each value represents the
current state of the cast, you can use the originalValue param if you need to work on the raw initial value.
var schema = yup.string().transform(function(currentValue, originalvalue){
return this.isType(value) && value !== null
? value.toUpperCase()
: value
});
schema.cast('jimmy') //=> 'JIMMY'
Each types will handle basic coercion of values to the proper type for you, but occasionally you may want to adjust or refine the default behavior. For example, if you wanted to use a different date parsing strategy than the default one you could do that with a transform.
yup.date().transform(function(formats = 'MMM dd, yyyy'){
//check to see if the previous transform already parsed the date
if ( this.isType(value) ) return value
//the default coercion failed so lets try it with Moment.js instead
value = Moment(originalValue, formats)
//if its valid return the date object, otherwise return an `InvalidDate`
return date.isValid() ? date.toDate() : new Date('')
})
Define a string schema. Supports all the same methods as mixed.
var schema = yup.string();
schema.isValid('hello') //=> true
By default, the cast logic of string is to call toString on the value if it exists.
empty values are not coerced (use ensure() to coerce empty values to empty strings).
Failed casts return the input value.
string.required(message: ?string): SchemaThe same as the mixed() schema required, except that empty strings are also considered 'missing' values.
To allow empty strings but fail on undefined values use: string().required().min(0)
string.min(limit: number | Ref, message: ?string): SchemaSet an minimum length limit for the string value. The ${min} interpolation can be used in the message argument
string.max(limit: number | Ref, message: ?string): SchemaSet an maximum length limit for the string value. The ${max} interpolation can be used in the message argument
string.matches(regex: Regex, message: ?string): SchemaProvide an arbitrary regex to match the value against.
var v = string().matches(/(hi|bye)/);
v.isValid('hi').should.eventually().equal(true)
v.isValid('nope').should.eventually().equal(false)
string.email(message: ?string): SchemaValidates the value as an email address via a regex.
string.url(message: ?string): SchemaValidates the value as a valid URL via a regex.
string.ensure(): SchemaTransforms undefined and null values to an empty string along with
setting the default to an empty string.
string.trim(message: ?string): SchemaTransforms string values by removing leading and trailing whitespace. If
strict() is set it will only validate that the value is trimmed.
string.lowercase(message: ?string): SchemaTransforms the string value to lowercase. If strict() is set it
will only validate that the value is lowercase.
string.uppercase(message: ?string): SchemaTransforms the string value to uppercase. If strict() is set it
will only validate that the value is uppercase.
Define a number schema. Supports all the same methods as mixed.
var schema = yup.number();
schema.isValid(10) //=> true
The default cast logic of number is: parseFloat.
Failed casts return NaN.
number.min(limit: number | Ref, message: ?string): SchemaSet the minimum value allowed. The ${min} interpolation can be used in the
message argument.
number.max(limit: number | Ref, message: ?string): SchemaSet the maximum value allowed. The ${max} interpolation can be used in the
message argument.
number.positive(message: ?string): SchemaValue must be a positive number.
number.negative(message: ?string): SchemaValue must be a negative number.
number.integer(message: ?string): SchemaValidates that a number is an integer.
number.truncate(): SchemaTransformation that coerces the value to an integer by stripping off the digits to the right of the decimal point.
number.round(type: 'floor' | 'ceil' | 'trunc' | 'round' = 'round'): SchemaAdjusts the value via the specified method of Math (defaults to 'round').
Define a boolean schema. Supports all the same methods as mixed.
var schema = yup.boolean();
schema.isValid(true) //=> true
Define a Date schema. By default ISO date strings will parse correctly,
for more robust parsing options see the extending schema types at the end of the readme.
Supports all the same methods as mixed.
var schema = yup.date();
schema.isValid(new Date) //=> true
The default cast logic of date is pass the value to the Date constructor, failing that, it will attempt
to parse the date as an ISO date string.
Failed casts return an invalid Date.
date.min(limit: Date | string | Ref, message: ?string): SchemaSet the minimum date allowed. When a string is provided it will attempt to cast to a date first and use the result as the limit.
date.max(limit: Date | string | Ref, message: ?string): SchemaSet the maximum date allowed, When a string is provided it will attempt to cast to a date first and use the result as the limit.
Define an array schema. Arrays can be typed or not, When specifying the element type, cast and isValid
will apply to the elements as well. Options passed into isValid are passed also passed to child schemas.
Supports all the same methods as mixed.
var schema = yup.array().of(number().min(2));
schema.isValid([2, 3]) //=> true
schema.isValid([1, -24]) //=> false
schema.cast(['2', '3']) //=> [2, 3]
You can also pass a subtype schema to the array constructor as a convenience.
array().of(number())
//or
array(number())
The default cast behavior for array is: JSON.parse
Failed casts return: null;
array.of(type: Schema): SchemaSpecify the schema of array elements. of() is optional and when omitted the array schema will
not validate its contents.
array.required(message: ?string): SchemaThe same as the mixed() schema required, except that empty arrays are also considered 'missing' values.
To allow empty arrays but fail on undefined values use: array().required().min(0)
array.min(limit: number | Ref, message: ?string): SchemaSet an minimum length limit for the array. The ${min} interpolation can be used in the message argument.
array.max(limit: number | Ref, message: ?string): SchemaSet an maximum length limit for the array. The ${max} interpolation can be used in the message argument.
array.ensure(): SchemaEnsures that the value is an array, by setting the default to [] and transforming null and undefined
values to an empty array as well. Any non-empty, non-array value will be wrapped in an array.
array().ensure().cast(null) // -> []
array().ensure().cast(1) // -> [1]
array().ensure().cast([1]) // -> [1]
array.compact(rejector: (value) => boolean): SchemaRemoves falsey values from the array. Providing a rejecter function lets you specify the rejection criteria yourself.
array()
.compact()
.cast(['', 1, 0, 4, false, null]) // => [1,4]
array()
.compact(function(v){
return v == null
})
.cast(['', 1, 0, 4, false, null]) // => ['',1, 0, 4, false]
Define an object schema. Options passed into isValid are also passed to child schemas.
Supports all the same methods as mixed.
yup.object().shape({
name: string().required(),
age: number().required().positive().integer(),
email: string().email(),
website string().url(),
})
You can also pass a shape to the object constructor as a convenience.
object().shape({
num: number()
})
//or
object({
num: number()
})
The default cast behavior for object is: JSON.parse
Failed casts return: null;
object.shape(fields: object, noSortEdges: ?Array<[string, string]>): SchemaDefine the keys of the object and the schemas for said keys.
object.from(fromKey: string, toKey: string, alias: boolean = false): SchemaTransforms the specified key to a new key. If alias is true then the old key will be left.
var schema = object({
myProp: mixed(),
Other: mixed(),
})
.from('prop', 'myProp')
.from('other', 'Other', true)
inst.cast({ prop: 5, other: 6}) // => { myProp: 5, other: 6, Other: 6 }
object.noUnknown(onlyKnownKeys: boolean = true, message: ?string): SchemaValidate that the object value only contains keys specified in shape, pass false as the first
argument to disable the check. Restricting keys to known, also enables stripUnknown option, when not in strict mode.
object.camelCase(): SchemaTransforms all object keys to camelCase
object.constantCase(): SchemaTransforms all object keys to CONSTANT_CASE.
The simplest way to extend an existing type is just to cache a configured schema and use that through your application.
var yup = require('yup');
var parseFormats = ['MMM dd, yyy']
var invalidDate = new Date('');
module.exports = yup.date()
.transform(function(value, originalValue){
if ( this.isType(value) ) return value
//the default coercion transform failed so lets try it with Moment instead
value = Moment(originalValue, parseFormats)
return date.isValid() ? date.toDate() : invalidDate
})
Alternatively, each schema is a normal JavaScript constructor function that you can mutate or delegate to
using the normal patterns. Generally you should not inherit from mixed unless you know what you are doing,
better to think of it as an abstract class. The other types are fair game though.
You should keep in mind some basic guidelines when extending schemas
clone() and then mutate the new one before returning it.
Built-in methods like test and transform take care of this for you, so you can safely use them (see below) without worryingvalue passed in, and should return an invalid object when one exists
(NaN, InvalidDate, etc) instead of null for bad values.value is guaranteed to be the correct type, however if nullable is
set then null is a valid value for that type, so don't assume that a property or method exists on the value.Adjust core Types
var invalidDate = new Date('');
function parseDateFromFormats(formats, parseStrict) {
return this.transform(function(value, originalValue){
if (this.isType(value))
return value
value = Moment(originalValue, formats, parseStrict)
return date.isValid() ? date.toDate() : invalidDate
})
}
// `addMethod` doesn't do anything special it's
// equivalent to: yup.date.protoype.format = parseDateFromFormats
yup.addMethod(yup.date, 'format', parseDateFromFormats)
Creating new Types
Yup schema use the common constructor pattern for modeling inheritance. You can use any utility or pattern that works with that pattern. The below demonstrates using the es6 class syntax since its less verbose, but you absolutely aren't required to use it.
var DateSchema = yup.date
var invalidDate = new Date(''); // our failed to coerce value
class MomentDateSchemaType extends DateSchema {
constructor() {
super();
this._validFormats = [];
this.withMutation(() => {
this.transform(function (value, originalvalue) {
if (this.isType(value)) // we have a valid value
return value
return Moment(originalValue, this._validFormats, true)
})
})
}
_typeCheck(value) {
return super._typeCheck(value)
|| (moment.isMoment(value) && value.isValid())
}
format(formats) {
if (!formats)
throw new Error('must enter a valid format')
let next = this.clone()
next._validFormats = {}.concat(formats);
}
}
var schema = new MomentDateSchemaType()
schema
.format('YYYY-MM-DD')
.cast('It is 2012-05-25') // Fri May 25 2012 00:00:00 GMT-0400 (Eastern Daylight Time)
FAQs
Dead simple Object schema validation
The npm package yup receives a total of 6,236,283 weekly downloads. As such, yup popularity was classified as popular.
We found that yup demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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